Pharmaceuticals compositions

ABSTRACT

Pharmaceutical compositions containing 2,6-diisopropylphenol (propofol) are described for use as anesthetics.  
     A method for their preparation is described, as their use in producing anesthesia including induction and maintenance of general anesthesia and sedation.

[0001] The present invention relates to 2,6-diisopropylphenol, known aspropofol, and in particular to new pharmaceutical compositionscontaining propofol.

[0002] Propofol is an injectable anaesthetic which has hypnoticproperties and can be used to induce and maintain general anaesthesiaand for sedation for example in Intensive Care Units. Propofol is ahighly successful anaesthetic and is marketed under the trademark‘Diprivan’ for use in treating humans and under the trademark‘Rapinovet’ for veterinary use.

[0003] Injectable anaesthetics, such as propofol, are administereddirectly into the blood stream. This gives rise to a rapid onset ofanaesthesia influenced almost entirely by the rate at which theanaesthetic agent crosses the blood-brain barrier. It is thereforenecessary for the anaesthetic agent to have sufficient lipid solubilityto be able to cross this barrier and depress the relevant mechanisms ofthe brain. However highly lipid soluble molecules are generally poorlysoluble in water and thus are difficult to formulate for intravenousinjection. In some cases it may be possible to obtain a water solublesalt of the anaesthetic agent which releases a lipid soluble free basein vivo. This is not possible in many cases and, despite considerableresearch, it did not prove to be feasible with propofol. Thus it wasnecessary to conduct very substantial research and development into theformulation of propofol in order to obtain pharmaceutical compositionsfor administration to warm-blooded animals including humans.

[0004] The present applicants identified the anaesthetic properties ofpropofol and filed UK patent application no 13739/74 which was grantedas United Kingdom Patent 1472793. Corresponding patents have beengranted in the USA (U.S. Pat. No. 4,056,635, 4,452,817 and 4,798,846)and many other territories.

[0005] This patent claims inter alia a sterile pharmaceuticalcomposition which comprises propofol in association with a sterilepharmaceutically-acceptable diluent or carrier the composition beingsuitable either directly or after dilution with a liquid diluent forparenteral administration to a warm-blooded animal.

[0006] In one aspect, UK 1472793 described the composition as preferablyaqueous with propofol in sterile admixture with water and a surfactantor other solubilising agent. In another aspect the composition wasdescribed as aqueous with propofol in sterile admixture with water andan additional water-miscible, non-aqueous solvent. In a further aspectthe composition was described as an oil-in-water emulsion in whichpropofol, either alone or dissolved in a water-immiscible solvent, isemulsified with water by means of a surfactant. In yet a further aspectthe composition was described as a sterile solid or semi-solid mixtureof propofol with a solid diluent, for example lactose, saccharin sodiumor a cyclodextran which composition is suitable for dilution with asterile aqueous diluent.

[0007] The patent describes many particular Examples of injectablecompositions containing propofol including Examples with varioussurfactants, various solubilising agents, additional solvents,additional constituents (selected from stabilisers, preservatives andantioxidants), buffering agents and tonicity modifiers.

[0008] The present applicants conducted a wide range of studies todetermine which type of formulation would be most appropriate fordevelopment to provide a formulation for marketing. After considerableeffort a formulation of propofol and the surfactant Cremophor EL(Cremophor is a trade mark for a polyoxyethylene castor oil derivative)in water was selected. Cremophor EL was used as the carrier tosolubilise the existing intravenous anaesthetic alphaxalone/alphadolone(‘Althesin’) and a modified form of Cremophor was used as the carrier tosolubilise the intravenous anaesthetic propanidid (‘Epontol’).

[0009] The present applicants conducted a detailed series of studies inanimals and ultimately administered the formulation to over 1000 humans.However, after about five or six years, anaphylactoid reactions werereported in a very small number of patients. Anaphylactoid reactions areallergic-type reactions. It was not clear that Cremophor EL had causedthe anaphylactoid reactions in all instances but the present applicantsconcluded that an alternative formulation of propofol would have to befound and developed.

[0010] A substantial amount of work on alternative formulations wasperformed and an oil-in-water emulsion was eventually selected fordevelopment. This was developed and in 1986 was launched in a number ofmarkets under the trade mark ‘Diprivan’. Since then this formulation hasbeen launched in many markets throughout the world and propofol ishighly successful being regarded by anaesthetists as a drug of greatmerit having unique qualities. In summary propofol is a short-actinganaesthetic, suitable for both induction and maintenance of generalanaesthesia, for sedation to supplement regional analgesic techniques,for sedation of ventilated patients receiving intensive care and forconscious sedation for surgical and diagnostic procedures in IntensiveCare Units. Propofol may be administered by single or repeatedintravenous bolus injections or by continuous infusion. It is veryrapidly removed from the blood stream and metabolised. Thus the depth ofanaesthesia is easily controlled and patient recovery on discontinuingthe drug is usually rapid and the patient is often significantly moreclear headed as compared to after administration of other anaesthetics.Side-effects such as nausea and vomiting occur significantly lessfrequently following administration of propofol than following othergeneral anaesthetic techniques such as with inhalational anaesthetics.

[0011] The present applicants have considered extending the range ofpropofol formulations in order to give the anaesthetist a widerarmamentarium from which to select an appropriate drug. For exampleapplicants have developed, as an alternative, an oil-in-water emulsionformulation of propofol wherein the concentration of propofol is twicethat of the presently marketed drug.

[0012] In considering appropriate further formulations it is desirableto maintain the qualities that make ‘Diprivan’ of such merit, such asthose aforementioned and provide a formulation with acceptable chemicaland physical stability and which is readily manipulable by theanaesthetist or Intensive Care Unit (ICU) specialist.

[0013] An increasing proportion of the usage of ‘Diprivan’ is in thesedation of seriously ill patients particularly in Intensive Care Unitsand the like. In the sedation of such seriously ill patientsadministration of ‘Diprivan’ is typically by means of infusion. Thisrequires the use of a ‘giving set’, which involves the linkage of areservoir (typically a vial or syringe) of propofol, via appropriatetubing, to a luer connector and thence to a needle positioned in thepatient's vein.

[0014] Microbial contamination of parenteral fluids used in ‘givingsets’ of this type has been recognised as one of many causes ofnosocomial infection amongst ICU patients. Accordingly, for example inthe USA, the general requirements of the Federal Food and DrugAdministration (FDA) are that such ‘giving sets’ are changed frequentlyand in the case of ‘Diprivan’, it is required that the ‘giving sets’ arechanged at least every 6 or 12 hours dependent on the presentation beingused.

[0015] Intensive Care environments are busy and, as in other parts ofthe health services, there are pressures for cost-containment. Thechanging of ‘giving sets’ at least every 6 or 12 hours is relativelytime-consuming for the highly skilled ICU nurse, Intensive CareSpecialist or anaesthetist. This would particularly be the case when anumber of seriously ill patients in an ICU are being infused at the sametime.

[0016] Therefore, the applicants have sought to develop a newformulation of propofol which would enable ‘giving sets’ to be changedsignificantly less frequently (for example every 24 hours). This wouldbe much more convenient for the nurse, Intensive Care Specialist oranaesthetist; would lower the pressure on staff, would result in fewermanipulations of ‘giving sets’ and may contribute to cost-saving in theICU environment.

[0017] We have conducted substantial research and have found that theaddition of small amounts of a selected agent to ‘Diprivan’ will enablethe formulation to be administered in ‘giving sets’ that requirechanging significantly less frequently than is presently the case; inother words the time for administration and time between changes of thegiving sets has been significantly improved. This increase in such timesenables packs of increased size to be administered, increasingconvenience for the users, decreasing wastage of ‘Diprivan’ andcontributing to cost-containment.

[0018] Furthermore, in the unlikely event of mishandling leading toaccidental extrinsic contamination, the formulation will minimise thechance of microbial growth.

[0019] Our own UK Patent 1472793 discloses that formulations of propofolmay optionally contain one or more additional constituents selected fromstabilisers, preservatives and antioxidants, for example parabensderivatives, for example propyl p-hydroxybenzoate, butylatedhydroxytoluene derivatives, ascorbic acid and sodium metabisulphite;metal ion sequestering agents, for example sodium edetate; andantifoaming agents, for example a silicone derivative, for exampledimethicone or simethicone.

[0020] There is a difficulty in the addition of known preservatives tooil-in-water emulsions such as ‘Diprivan’. As stated above, ‘Diprivan’is an anaesthetic used for induction and maintenance of generalanaesthesia and for sedation. The volumes administered can beconsiderable, particularly in the case of sedation. Accordingly,significant volumes of preservative may be administered to the patientreceiving treatment. Thus very careful selection of additive must bemade in order to satisfy drug Regulatory Authorities; particularly asthe use of preservatives in single-dose, terminally sterilised,parenteral injectables is not suggested and/or is the subject ofcautionary statements in various Guidelines, for example those of theUS, UK and European Pharmacopeias.

[0021] Furthermore there is a particular problem in the inclusion ofadditives in an oil-in-water emulsion for parenteral administration. Itis believed that for effectiveness, the antimicrobial properties of anypreservative have to be exerted in the aqueous phase. Thus, apreservative with lipophilic properties incorporated at typical usagelevels would not be effective as, although there would be somepartitioning between the phases, there would be insufficient material inthe aqueous phase. Increasing the overall quantity of such preservativewould result in unacceptably high levels of preservative in the lipidlayer leading to toxicity problems at least.

[0022] On the other hand, addition of a preservative with hydrophilicproperties, eg an ionic material, also leads to problems. The additionof ionic material to an oil-in-water emulsion tends to destabilise theemulsion. With a higher ionic load (that is concentration of ionicmaterial) the stabilising electrical charge (Zeta potential) on the oilydroplets can change. Such electrical charge changes increase theprobability of droplet collisions and increase the physical instabilityof the emulsion.

[0023] We studied the possibility of adding one of a number ofantimicrobial agents to the oil-in-water emulsion. Such an agent wouldhave to have no significant detrimental effect on the physical andchemical stability of the emulsion. Furthermore, such an agent wouldhave to provide the antimicrobial activity being sought.

[0024] A number of potential agents were found to cause instability ofthe emulsion. Other potential agents failed to provide the level ofantimicrobial activity being sought. In addition, we were seeking anagent that would provide these levels of activity at as low aconcentration as possible in order to minimise the potential forphysical instability and to minimise safety concerns.

[0025] After significant effort including consideration of the knownpreservatives phenylmercuric acetate, phenylmercuric nitrate, benzylalcohol, chlorobutanol, chlorocresol and phenol and the study of theknown preservatives sodium metabisulphite, sodium sulphite, sodiummethyl hydroxybenzoate and sodium propyl hydroxybenzoate, we were unableto find a preservative that met our requirements. We then investigatedthe possible use of other agents which might have the action that wesought. We unexpectedly found that edetate, which is not regarded as abroad spectrum antimicrobial agent was the only agent that would meetour requirements. As referred to above, edetate as the sodium salt ismentioned in our UK Patent 1472793 as a possible metal ion sequesteringagent. Sodium edetate is included in two of the manyCremophor-containing examples of that Patent.

[0026] Accordingly the present invention provides a sterilepharmaceutical composition for parenteral administration which comprisesan oil-in-water emulsion in which propofol dissolved in awater-immiscible solvent, is emulsified with water and stabilised bymeans of a surfactant, and which further comprises an amount of edetatesufficient to prevent significant growth of microorganisms for at least24 hours (in the event of adventitious, extrinsic contamination).

[0027] By an oil-in-water emulsion we mean a distinct two-phase systemthat is in equilibrium and in effect, as a whole, is kinetically stableand thermodynamically unstable. This is in complete contrast to amicellar formulation, for example with Cremophor EL, which isthermodynamically stable.

[0028] By the term “edetate” we mean ethylenediaminetetraacetic acid(EDTA) and derivatives thereof, for example the disodium derivative isknown as disodium edetate. In general suitable edetates of thisinvention are those salts having lower affinity for EDTA than calcium.Particular derivatives of use in the present invention include trisodiumedetate, tetrasodium edetate and disodium calcium edetate. The nature ofthe edetate is not critical, provided that it fulfils the function ofpreventing significant growth of microorganisms for at least 24 hours inthe event of adventitious extrinsic contamination (e.g. preferably nomore than 10-fold increase following a low level of extrinsiccontamination, such as 10-10³ colony forming units, at temperatures inthe range of 20-25° C.). As can be seen from the experimental section,sodium calcium edetate has some advantages over other additives butdisodium edetate is exceptional. Accordingly, most preferably theedetate is disodium edetate.

[0029] Typically the edetate will be present in the compositions of thepresent invention in a molar concentration (with respect to the EDTAfree acid) in the range 3×10⁻⁵ to 9×10⁻⁴. Preferably the edetate ispresent in the range 3×10⁻⁵ to 7.5×10⁻⁴, for example in the range 5×10⁵to 5×10⁻⁴ and more preferably in the range 1.5×10⁴ to 3.0×10⁻⁴, mostpreferably about 1.5×10⁻⁴.

[0030] A composition of the present invention typically comprises from0.1 to 5%, by weight, of propofol. Preferably the composition comprisesfrom 1 to 2% by weight of propofol and, in particular, about 1% or about2%.

[0031] In another aspect of the invention propofol alone is emulsifiedwith water by means of a surfactant. It is preferred that propofol isdissolved in a water-immiscible solvent prior to emulsification.

[0032] The water-immiscible solvent is suitably present in an amountthat is up to 30% by weight of the composition, more suitably 5-25%,preferably 10-20% and in particular about 10%.

[0033] A wide range of water-immiscible solvents can be used in thecompositions of the present invention. Typically the-water-immisciblesolvent is a vegetable oil, for example soy bean, safflower, cottonseed,corn, sunflower, arachis, castor or olive oil. Preferably the vegetableoil is soy bean oil. Alternatively, the water-immiscible solvent is anester of a medium or long-chain fatty acid for example a mono-, di-, ortriglyceride; or is a chemically modified or manufactured material suchas ethyl oleate, isopropyl myristate, isopropyl palmitate, a glycerolester or polyoxyl hydrogenated castor oil. In a further alternative thewater-immiscible solvent may be a marine oil, for example cod liver oranother fish-derived oil. Suitable solvents also include fractionatedoils for example fractionated coconut oil or modified soy bean oil.Furthermore, the compositions of the present invention may comprise amixture of two or more of the above water-immiscible solvents.

[0034] Propofol, either alone or dissolved in a water-immisciblesolvent, is emulsified by means of a surfactant. Suitable surfactantsinclude synthetic non-ionic surfactants, for example ethoxylated ethersand esters and polypropylene-polyethylene block co-polymers, andphosphatides for example naturally occuring phosphatides such as egg andsoya phosphatides and modified or artificially manipulated phosphatides(for example prepared by physical fractionation and/or chromatography),or mixtures thereof. Preferred surfactants are egg and soyaphosphatides.

[0035] The composition of the present invention is suitably formulatedto be at physiologically neutral pH, typically in the range 6.0-8.5, ifnecessary by means of alkali such as sodium hydroxide.

[0036] The composition of the present invention may be made isotonicwith blood by the incorporation of a suitable tonicity modifier forexample glycerol.

[0037] The composition of the present inventions are typically sterileaqueous formulations and are prepared according to conventionalmanufacturing techniques using for example aseptic manufacture orterminal sterilisation by autoclaving.

[0038] The compositions of the present invention are useful asanaesthetics which includes sedation and induction and maintenance ofgeneral anaesthesia. Accordingly in another aspect the present inventionprovides a method of producing anaesthesia (including sedation andinduction and maintenance of general anaesthesia) in a warm-bloodedanimal, including humans, which comprises administering parenterally asterile aqueous pharmaceutical composition which comprises anoil-in-water emulsion in which propofol, either alone or in awater-immiscible solvent, is emulsified with water and stabilised bymeans of a surfactant and which further comprises an effective amount ofedetate.

[0039] Dosage levels of propofol for producing general anaesthesia, bothinduction (for example about 2.0-2.5 mg/kg for an adult) and maintenance(for example about 4-12 mg/kg/hr), and for producing a sedative effect(for example 0.3-4.5 mg/kg/hr), may be derived from the substantialliterature on propofol. Furthermore the anaesthetist and/or physicianwould modify the dose to achieve the desired effect in any particularpatient, in accordance with normal skill in the art.

[0040] The advantages referred to above for including edetate inpropofol compositions apply also to intravenous fat emulsions whichtypically are administered, to patients in need thereof, over periods ofa day or more. Intravenous fat emulsions (also known as parenteralnutrition emulsions) are administered, usually by infusion, to patientshaving requirements for additional calories and adequate nutrition, byoral or other means, is not desirable or is not possible. Intravenousfat emulsions typically maintain a positive nitrogen balance and providean adequate source of energy (e.g. as fat), vitamins and trace elements.Such emulsions are used typically in intensive care environments butalso in other hospital and domestic settings. Examples of suchintravenous fat emulsions include Intralipid (marketed by Pharmacia),Lipofundin (Braun) and Travamulsion (Baxter). Intralipid, Lipofundin andTravamulsion are all trademarks.

[0041] Accordingly in another aspect, the present invention provides anintravenous fat emulsion which comprises an amount of edetate sufficientto prevent significant growth of microorganisms for at least 24 hours.In particular the present invention provides a sterile, aqueouscomposition for parenteral administration which comprises anoil-in-water emulsion in which a water-immiscible solvent is emulsifiedwith water and stabilised by means of a surfactant and which furthercomprises an amount of edetate sufficient to prevent significant growthof microorganisms for at least 24 hours.

[0042] Furthermore, it has been proposed that various drugs may beadministered in oil-in-water emulsions, for example see U.S. Pat. No.4,168,308. Accordingly in a further aspect, the present inventionprovides a sterile, aqueous composition for parenteral administrationwhich comprises an oil-in-water emulsion containing a therapeutic orpharmaceutical agent, in which the agent, either alone or dissolved in awater-immiscible solvent, is emulsified with water and stabilised bymeans of a surfactant and which further comprises an amount of edetatesufficient to prevent significant growth of microorganisms for at least24 hours.

[0043] Suitable therapeutic or pharmaceutical agents are those capableof being administered parenterally in an oil-in-water emulsion.Typically such agents are lipophilic compounds and may for example beantifungal agents, anaesthetics, antibacterial agents, anti-canceragents, anti-emetics, agents acting on the central nervous system suchas diazepam, steroids, barbiturates and vitamin preparations. Inparticular the present invention relates to such oil-in-water emulsionswhich typically are administered, to patients in need thereof, overperiods of a day or more.

[0044] Comments herein relating to typical and preferred propofolcompositions of this invention and the preparation thereof apply mutatismutandis to intravenous fat emulsions and to oil-in-water emulsionscontaining a therapeutic or pharmaceutical agent.

EXPERIMENTAL

[0045] Quantities: % (weight) propofol 1.0 soy bean oil 10.0 eggphosphatide 1.2 glycerol 2.25 disodium edetate dihydrate 0.0055(equivalent to disodium edetate 0.005) sodium hydroxide q.s. Water forInjections to 100

[0046] Preparation:

[0047] All processing stages are carried out under Nitrogen and weightsrefer to weight in the final volume.

[0048] A sterile aqueous oil-in-water emulsion for parenteraladministration is prepared as follows:

[0049] 1. An aqueous phase is prepared from glycerol (2.25% by weight),disodium edetate dehydrate (0.0055% by weight), sodium hydroxide(typically 60 mgL⁻¹) and Water for Injections. This mixture is stirredand taken to a temperature of approximately 65° C.

[0050] 2. The aqueous phase is passed through a filter to removeparticulate matter and transferred to a mixing vessel.

[0051] 3. In parallel to the above, an oil phase is prepared from soybean oil (10.0% by weight), propofol (1.0% by weight) and eggphosphatide (1.2% by weight) in a vessel. The mixture is stirred at atemperature of approximately 75° C. until all ingredients are dissolved.

[0052] 4. The mixture is passed through a filter to remove particulatematter and added to the aqueous phase via a static mixer.

[0053] 5. The contents of the mixing vessel are stirred and maintainedat a temperature of approximately 65° C. This mixture is then circulatedthrough a high pressure homogeniser and cooler (heat exchange system)until the required globule size [mean globule size of approximately 250nanometers] is achieved.

[0054] 6. The resultant oil-in-water emulsion is cooled and transferredinto a filling vessel.

[0055] 7. The emulsion is then filtered and filled into containers undernitrogen-and autoclaved.

[0056] The final filtered emulsion may be filled into containers ofvarious volumes for example ampoules (20 ml), vials (50 ml and 100 ml)and pre-filled syringes.

[0057] Diagram:

[0058] An oil-in-water emulsion containing 2% (by weight) of propofolmay be prepared in a similar manner using the following quantities ofingredients: Quantities: % (weight) propofol 2.0 soy bean oil 10.0 eggphosphatide 1.2 glycerol 2.25 disodium edetate dihydrate 0.0055 sodiumhydroxide q.s. Water for Injections to 100

[0059] Further oil-in-water emulsions containing 1% (by weight) ofpropofol may be prepared in a similar manner using the followingquantities of ingredients: Quantities: % (weight) % (weight) propofol1.0 1.0 soy bean oil 5.0 — fractionated coconut oil (Miglyol 5.0 10.0812N) egg phosphatide 1.2 1.2 glycerol 2.25 2.25 disodium edetatedihydrate 0.0055 0.0055 sodium hydroxide q.s. q.s. Water for Injectionsto 100 to 100

[0060] Biological Activity

[0061] The formulations are administered parenterally to groups of 10male mice (18-22 g) at a dose of 5-40 mg/kg. Sedation and anaesthesiaare observed dependent on dose.

[0062] Microbiological Activity (Comparative)

[0063] Formulations containing various additives were prepared by addinga concentrated aqueous solution of the additive to the commerciallyavailable oil-in-water formulation of propofol (1%) (Diprivan: TradeHark of Zeneca Ltd). The pH of these formulations was approximately 7.5.

[0064] Broth cultures of four standard USP (United States pharmacopeia)preservative efficacy test organisms were added to these testformulations at approximately 200 colony forming units per ml. The testformulations were incubated at 30° C. and tested for viable counts after24 and 48 hours.

[0065] Results LOG₁₀ SURVIVORS PER ML Test Organism Zero 24 hours 48hours Formulation with sodium metabisulphite (0.1%) S. aureus 2.4 4.14.7 E. coli 2.2 8.9 8.7 C. albicans 2.8 4.4 7.9 Ps. aeruginosa 2.8 4.88.9

[0066] Discolouration of the formulation occurred showing chemicalinstability. LOG₁₀ SURVIVORS PER ML Test Organism Zero 24 hours 48 hoursFormulation with sodium sulphite (0.1%) S. aureus 2.8 5.7 6.2 E. coli1.6 7.8 8.9 C. albicans 2.9 4.1 5.8 Ps. aeruginosa 2.2 6.7 6.9Formulation with hydroxybenzoates (0.2% methyl/ 0.02% propyl) S. aureus2.9 6.6 6.7 E. coli 1.9 4.7 7.4 C. albicans 2.8 3.0 3.2 Ps. aeruginosa2.4 2.2 5.8 Formulation with sodium calcium edetate (0.1%) S. aureus 2.23.3 6.9 E. coli 2.6 <1.3 <1.3 C. albicans 2.9 3.1 3.8 Ps. aeruginosa 2.86.8 8.2 Formulation with disodium edetate dihydrate (0.1%) [pHapproximately 5.5] S. aureus 0.7 0.3 <1.0 E. coli 1.2 0.3 <1.0 C.albicans 1.0 0.8 <1.0 Ps. aeruginosa 1.3 <1.0 <1.0

[0067] Microbiological Activity (Further Comparative Results)

[0068] Washed suspensions of four standard USP (United StatesPharmacopeia) preservative efficacy test organisms were added to thesetest formulations at approximately 100 colony forming units per ml. Thetest formulations were incubated at 25° C. and tested for viable countsafter 24 and 48 hours in duplicate; both results are reported. LOG₁₀SURVIVORS PER HL Test Organism Zero 24 hours 48 hours ‘Diprivan’ (1%propofol) S. aureus 2.0 4.3 5.7 2.0 4.6 5.7 E. coli 1.7 8.1 7.9 1.6 7.88.1 C. albicans 1.5 2.8 2.6 1.5 2.8 3.6 Ps. aeruginosa 1.5 4.9 8.4 1.53.9 8.0 Formulation with disodium edetate dihydrate (0.0055%) S. aureus2.0 1.3 0.5 2.0 1.1 1.0 E. coli 1.6 1.1 ND 1.4 1.1 ND C. albicans 1.61.6 2.0 1.5 1.3 2.1 Ps. aeruginosa 1.6 1.0 0.8 1.5 ND 0.7

[0069] The above formulation has been further assessed against otherrelevant organisms.

[0070] In a similar manner, microbiological data have been obtained forthe corresponding formulation containing 2% propofol.

[0071] Intravenous Fat Emulsion

[0072] [comprising soy bean oil (10%), egg phosphatide (1.2%), glycerol(2.25%), sodium hydroxide (qs) and Water for Injections] LOG₁₀ SURVIVORSPER ML Test Organism Zero 24 hours 48 hours S. aureus 2.0 6.5 6.6 2.06.6 6.7 E. coli 1.5 8.0 8.3 1.6 7.9 8.1 C. albicans 1.5 1.2 6.0 1.4 3.55.6 Ps. aeruginosa 1.3 6.6 8.1 1.5 6.9 8.1 Intravenous fat emulsion (asabove) with disodium edetate dihydrate (0.0055%) S. aureus 2.0 1.4 ND2.0 1.4 ND E. coli 1.6 ND ND 1.5 ND ND C. albicans 1.5 1.8 2.4 1.5 2.12.2 Ps. aeruginosa 1.6 ND ND 1.5 ND ND

[0073] The above formulation has been further assessed against otherrelevant organisms.

[0074] The test organisms identified above are Staphylococcus aureusATCC 6538, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027and Candida albicans ATCC 10231.

[0075] In a preferred embodiment the present invention provides asterile pharmaceutical composition which comprises an oil-in-wateremulsion in which propofol, dissolved in a water-immiscible solvent, isemulsified with water and stabilised by means of a surfactant, and whichfurther comprises an amount of edetate sufficient to prevent a no morethan 10-fold increase in growth of each of Staphylococcus aureus ATCC6538, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 andCandida albicans ATCC 10231 for at least 24 hours as measured by a testwherein a washed suspension of each said organism is added to a separatealiquot of said composition at approximately 50 colony forming units perml, at a temperature in the range 20-25° C., said aliquots are incubatedat 20-25° C. and are tested for viable counts after 24 hours.

1. A sterile pharmaceutical composition for parenteral administrationwhich comprises an oil-in-water emulsion in which propofol dissolved ina water-immiscible solvent, is emulsified with water and stabilised bymeans of a surfactant, and which further comprises an amount of edetatesufficient to prevent significant growth of microorganisms for at least24 hours after adventitious, extrinsic contamination.
 2. A sterilepharmaceutical composition according to claim 1 wherein the amount ofedetate is sufficient to prevent a no more than 10-fold increase ingrowth of clinically relevant microorganisms for at least 24 hours aftercontamination by up to 10 colony forming units (at a temperature in therange 20-25° C.).
 3. A sterile pharmaceutical composition according toclaim 2 wherein the clinically relevant microorganisms are selected fromstrains of Staphylococcus aureus, Escherichia coli, Candida albicans andPseudomonas aeruginosa.
 4. A sterile pharmaceutical compositionaccording to claim 1 which comprises an oil-in-water emulsion in whichpropofol dissolved in a water-immiscible solvent, is emulsified withwater and stabilised by means of a surfactant, and which furthercomprises an amount of edetate sufficient to prevent a no more than10-fold increase in growth of each of Staphylococcus aureus ATCC 6538,Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Candidaalbicans ATCC 10231 for at least 24 hours as measured by a test whereina washed suspension of each said organism is added to a separate aliquotof said composition at approximately 50 colony forming units per ml, ata temperature in the range 20-25° C., said aliquots are incubated at20-25° C. and are tested for viable counts after 24 hours.
 5. A sterilepharmaceutical composition according to any one of claims 1 to 4 whereinthe edetate is disodium edetate.
 6. A sterile pharmaceutical compositionaccording to claim 1 which comprises up to about 30% by weight ofwater-immiscible solvent.
 7. A sterile pharmaceutical compositionaccording to claim 4 which comprises up to about 30% by weight ofwater-immiscible solvent.
 8. A sterile pharmaceutical compositionaccording to claim 6 which comprises from about 10% to about 20% byweight of water-immiscible solvent.
 9. A sterile pharmaceuticalcomposition according to claim 7 which comprises from about 10% to about20% by weight of water-immiscible solvent.
 10. A sterile pharmaceuticalcomposition according to any one of claims 1 to 4 wherein thewater-immiscible solvent is a vegetable oil or ester of a fatty acid.11. A sterile pharmaceutical composition according to claim 10 whereinthe vegetable oil is soy bean oil.
 12. A sterile pharmaceuticalcomposition according to any one of claims 1 to 4 wherein the surfactantis a naturally occurring phosphatide.
 13. A sterile pharmaceuticalcomposition according to claim 12 wherein the phosphatide is eggphosphatide or soya phosphatide.
 14. A sterile pharmaceuticalcomposition according to any one of claims 1 to 4 wherein the pH isbetween about 6.0 and about 8.5.
 15. A sterile pharmaceuticalcomposition according to claim 14 wherein sodium hydroxide is present.16. A sterile pharmaceutical composition according to any one of claims1 to 4 which is isotonic with blood.
 17. A sterile pharmaceuticalcomposition according to claim 16 which is made isotonic with blood byincorporation of glycerol.
 18. A sterile pharmaceutical compositionaccording to any one of claims 1-4 which comprises from about 1% toabout 2% by weight of propofol.
 19. A sterile pharmaceutical compositionaccording to claim 18 which contains about 1% by weight of propofol. 20.A sterile pharmaceutical composition according to claim 18 whichcontains about 2% by weight of propofol.
 21. A sterile pharmaceuticalcomposition for parenteral administration which comprises anoil-in-water emulsion in which propofol dissolved in a water-immisciblesolvent, is emulsified with water and stabilised by means of asurfactant, and which further comprises an amount of edetate wherein theamount of edetate is a molar concentration in the range 3×10⁻⁵ to9×10⁻⁴.
 22. A sterile pharmaceutical composition according to claim 21wherein the amount of edetate is a molar concentration in the range3×10⁵ to 7.5×10⁻⁴.
 23. A sterile pharmaceutical composition according toclaim 22 wherein the amount of edetate is a molar concentration in therange 1.5×10⁻⁴ to 3.0×10⁻⁴.
 24. A sterile pharmaceutical compositionaccording to claim 23 wherein the amount of edetate is a molarconcentration of about 1.5×10⁻⁴.
 25. A sterile pharmaceuticalcomposition according to any one of claims 21 to 24 wherein the sourceof edetate is disodium edetate.
 26. A sterile pharmaceutical compositionaccording to claim 21 which comprises up to about 30% by weight ofwater-immiscible solvent.
 27. A sterile pharmaceutical compositionaccording to claim 26 which comprises from about 10% to about 20% byweight of water-immiscible solvent.
 28. A sterile pharmaceuticalcomposition according to any one of claims 21 to 24 wherein thewater-immiscible solvent is a vegetable oil or ester of a fatty acid.29. A sterile pharmaceutical composition according to claim 28 whereinthe vegetable oil is soy bean oil.
 30. A sterile pharmaceuticalcomposition according to any one of claims to 21 to 24 wherein thesurfactant is a naturally occurring phosphatide.
 31. A sterilepharmaceutical composition according to claim 30 wherein the phosphatideis egg phosphatide or soya phosphatide.
 32. A sterile pharmaceuticalcomposition according to any one of claims 21 to 24 wherein the pH isbetween about 6.0 and about 8.5.
 33. A sterile pharmaceuticalcomposition according to claim 32 wherein sodium hydroxide is present.34. A sterile pharmaceutical composition according to any one of claims21 to 24 which is isotonic with blood.
 35. A sterile pharmaceuticalcomposition according to claim 34 which is made isotonic with blood byincorporation of glycerol.
 36. A sterile pharmaceutical compositionaccording to any one of claims 21 to 24 which comprises from about 1% toabout 2% by weight of propofol.
 37. A sterile pharmaceutical compositionaccording to claim 36 which contains about 1% by weight of propofol. 38.A sterile pharmaceutical composition according to claim 36 whichcontains about 2% by weight of propofol.
 39. A sterile pharmaceuticalcomposition for parenteral administration in the form of an oil-in-wateremulsion which comprises: a) about 1% by weight of propofol, b) about10% by weight of soy bean oil, c) about 1.2% by weight of eggphosphatide, d) about 2.25% by weight of glycerol, e) about 0.005% byweight of disodium edetate, f) sodium hydroxide g) water to 100%.
 40. Asterile pharmaceutical composition for parenteral administration in theform of an oil-in-water emulsion which comprises: a) about 2% by weightof propofol, b) about 10% by weight of soy bean oil, c) about 1.2% byweight of egg phosphatide, d) about 2.25% by weight of glycerol, e)about 0.005% by weight of disodium edetate, f) sodium hydroxide g) waterup to 100%.
 41. A method for limiting the potential for microbial growthin a sterile pharmaceutical composition for parenteral administrationwhich comprises the use of edetate in an oil-in-water emulsion in whichpropofol dissolved in a water-immiscible solvent, is emulsified withwater and stabilised by means of a surfactant, wherein the amount ofedetate is sufficient to prevent significant growth of microorganismsfor at least 24 hours after adventitious, extrinsic contamination.
 42. Amethod for limiting the potential for microbial growth in a sterilepharmaceutical composition for parenteral administration which comprisesthe use of edetate in an oil-in-water emulsion in which propofoldissolved in a water-immiscible solvent, is emulsified with water andstabilised by means of a surfactant, wherein the amount of edetate is amolar concentration in the range 3×10⁻⁵ to 9×10⁻⁴.
 43. A method ofproducing anaesthesia in a warm-blooded animal which comprisesadministering an effective amount of a sterile pharmaceuticalcomposition according to any one of claims 1 to
 4. 44. A method ofproducing anaesthesia in a warm-blooded animal which comprisesadministering an effective amount of a sterile pharmaceuticalcomposition according to any one of claims 21 to
 24. 45. A method ofproducing anaesthesia in a warm-blooded animal which comprisesadministering an effective amount of a sterile pharmaceuticalcomposition according to either claim 39 or claim
 40. 46. A sterilepharmaceutical composition for parenteral administration which comprisesan oil-in-water emulsion in which propofol is emulsified with water andstabilised by means of a surfactant, and which further comprises anamount of edetate sufficient to prevent significant growth ofmicroorganisms for at least 24 hours after adventitious, extrinsiccontamination.
 47. A sterile pharmaceutical composition for parenteraladministration which comprises an oil-in-water emulsion in whichpropofol is emulsified with water and stabilised by means of asurfactant, and which further comprises an amount of edetate wherein theamount of edetate is a molar concentration in the range 3×10⁻⁵ to9×10⁻⁴.
 48. A method for limiting the potential for microbial growth ina sterile pharmaceutical composition for parenteral administration whichcomprises the use of edetate in an oil-in-water emulsion in whichpropofol is emulsified with water and stabilised by means of asurfactant, wherein the amount of edetate is sufficient to preventsignificant growth of microorganisms for at least 24 hours afteradventitious, extrinsic contamination.
 49. A method for limiting thepotential for microbial growth in a sterile pharmaceutical compositionfor parenteral administration which comprises the use of edetate in anoil-in-water emulsion in which propofol is emulsified with water andstabilised by means of a surfactant, wherein the amount of edetate is amolar concentration in the range 3×10⁻⁵ to 9×10⁻⁴.
 50. A method ofimproving the time for administration, and/or the time between thechanges of giving sets, for an oil-in-water emulsion of propofol byincluding in said emulsion an amount of edetate sufficient to preventsignificant growth of microorganisms for at least 24 hours afteradventitious, extrinsic contamination.
 51. A method of improving thetime for administration, and/or the time between the changes of givingsets, for an oil-in-water emulsion of propofol by including in saidemulsion edetate in a molar concentration in the range 3×10⁻⁵ to 9×10⁻⁴.52. A sterile pharmaceutical composition for parenteral administrationwhich comprises an oil-in-water emulsion in which propofol dissolved ina water-immiscible solvent is emulsified with water and stabilised bymeans of a surfactant, and which further comprises an amount of edetatesufficient to prevent significant growth of microorganisms for at least24 hours after adventitious, extrinsic contamination wherein the edetatedoes not physically destabilise said composition.
 53. A sterilepharmaceutical composition for parenteral administration which comprisesan oil-in-water emulsion in which propofol dissolved in awater-immiscible solvent is emulsified with water and stabilised bymeans of a surfactant, and which further comprises an amount of edetatewherein the amount of edetate is a molar concentration in the range3×10⁻⁵ to 9×10⁻⁴ and does not physically destabilise said composition.54. A sterile, aqueous composition for parenteral administration whichcomprises an oil-in-water emulsion which is emulsified with water andstabilised by means of a surfactant and which further comprises anamount of edetate sufficient to prevent significant growth ofmicroorganisms for at least 24 hours after adventitious, extrinsiccontamination.
 55. A sterile, aqueous composition for parenteraladministration which comprises an oil-in-water emulsion which isemulsified with water and stabilised by means of a surfactant, and whichfurther comprises an amount of edetate wherein the amount of edetate isa molar concentration in the range 3×10⁻⁵ to 9×10⁻⁴.
 56. A sterilepharmaceutical composition which comprises an oil-in-water emulsioncontaining a therapeutic or pharmaceutical agent, in which the agent,either alone or dissolved in a water-immiscible solvent, is emulsifiedwith water and stabilised by means of a surfactant and which furthercomprises an amount of edetate sufficient to prevent significant growthof microorganisms for at least 24 hours after adventitious, extrinsiccontamination.
 57. A sterile pharmaceutical composition which comprisesan oil-in-water emulsion containing a therapeutic or pharmaceuticalagent, in which the agent, either alone or dissolved in awater-immiscible solvent, is emulsified with water and stabilised bymeans of a surfactant and which further comprises an amount of edetatewherein the amount of edetate is a molar concentration in the range3×10⁻⁵ to 9×10⁻⁴.
 58. A composition according to claim 56 comprising anantifungal agent, anaesthetic, antibacterial agent, anti-cancer agent,anti-emetic, agent acting on the central nervous system, steroid,barbiturate or a vitamin preparation.
 59. A composition according toclaim 56 comprising an antifungal agent, anaesthetic, antibacterialagent, anti-cancer agent, anti-emetic, agent acting on the centralnervous system, steroid, barbiturate or a vitamin preparation.